Portable stool



Aug. 6, 1929. M. w. MCARDLE PORTABLE STOOL Filed June 11, 1925 Patented ug.k 6, 1929.

MICHAEL W. MeARnLn,

OF CHICAGO, ILLINOIS.

PORTABLE STOOL.

Application filed lJune 11,

The purpose et this invention is to provide a novel torni oit portable stool adapted for a wide range otE utility by reason of independent vertical adjustability of seat and toot rest, and reino 'ability ot the foot rest, and the provision of an easily mounted and easily removable back, and by other detail leatures, constituting with the foregoing, parts et the invention, as indicated in the claims. y

In the drawings i- Figure 1 is a perspective view oit a stool embodying this invention which is shown equipped with a removable back and footy rest. t y

Figure 2 is a horizontal section at a plane between the seat and the toot rest.

Figure 3 is a section at the line 3 3 on Figure 2.

Figure 4t is a perspective view ot the removable back .member separated from the stool. i f f Figure 5 is a detail section at the line,5-5, on l, axial with respect to two of they back supports at its engagement with the seat when the back is mounted.

Figure G a detail sect-ion at the line 6-6 on Figure In the drawings, 10 a tripod base 'for the stool, having a sleeve stem or hub, 11., in-

teriorly threaded as seen at 1 2 for receiving the threaded stem, 13, ot the seat, 11i, which is a sheet metal stamping having a cast iron central reinforce, 15, whose central boss or hub, 16, is bored and threaded for screwing onto the upper endet the seat stem, 1%. Incidentally, it may be noted that each of the three feet, l0, ol" the tripod base is a metal stamping and that the sleeve stem or hub, 11, has at its lower end three horizontally radiatin arms, 11, to which the metal stamping toet are secured by bolts, 11b, the radial arn'is, 11, being laterally flanged as seen at 1l, forming channels on the underside diniensioncd tor snug lit therein ot the upper inner ends olf the metal stamping iteet, 10th The sleeve stem,'11, isr exteriorly diametered ttor easy lit thereon of the hollow cylindrical hub hereinafter referred to as the sleeve hub, 1G, ot a foot resi comprising the arcuate tread member, 1.7", radial arms, 17, 17, connecting the tread and sleeve hub 16, and a depressed yol-:e member, 17, which spans the angle between the radial. arms, 17, back oit the tread and by its depressed middle part,

1926. serial No. 115,193,y

affords lodgment upon and engagement with one ot the tripod leet, 10a, above which the tread, 17D, is medially positioned for a reason hereinafter pointed out.

In order to render the ioot rest adjustable vertically relatively to the seat, and therefore independently ot the seat, and at the same time to ensure the position ot the toot rest directly over one of the tripod feet, the sleeve stem or hub, 11,of the tripod base has a superlicialy longitudinally extending groove, 11d,-in whose bottom there are forme-d at short intervals in the length of the groove set screw seats, 11e, which may consist of f holes bored entirely through the thickness of the sleeve into the axial cavity thereof; and the sleeve hub, 16, of the foot rest, preferably at an exteriorly protruding boss, 16, is bored and. tapped tor a set screw, 18, which is reduced in diameter at its end portion for a short distance as seen at 18a to adapt said .reduced end to enter any one of the seats, 11. It will be understood that the groove, 11, serves for engagement et the reduced end, 18, oit' the set screw, 18, when the set screw is only partially screwed in, for guiding the toot rest in vertical adjustment and keeping it throughout such adjustment in desired position ydirectly over one ot the tripod feet; and that the seats, 11e, serve for positioning the toot rest at the desired vertical adjustment, the set screw being screwed home when the reduced terminal is registered with the seat corresponding most nearly7i to the desire-d height oit' the foot rest, the set screw being initially screwed in to cause the reduced end to touch the bottom of the f groove, the slackness of lit of the toot rest sleeve on its tripod stem enabling the operator to recognize the registration of the set screw'V terminal with'the set' screw seat; the tightening of the set screw thus operating to add the frictional engagement of the sleeves 11 and 16 to the shearing strength of the reduced terminal for holding the toot rest against depression along the tripod sleeve when it receives the loa-d ot the stool occupants feet. It may be understood also that the purpose of locating the foot rest directly above one ot the tripod feet and constructing the means of vertical adjustment so as to maintain that relation of the parts is that in' the case ot a three-legged support the value of the spread ot the lect for ensuring against ltipping over is available to the full limit only at the vertical radial planes in which the feet rest upon the floor, and that, therefore,

if the toot rest could swing around so as to overhang, for example, the middle part ot' the arc between the 'feet ot the tripod, onehaltl oft the value of the spread of the tripod feet tor stability as against the tendency ot' weight on the foot rest to tip the stool over,

would be lost` because the mid point in the chord ot the are between two feet of the tripod is only one-halt as tar from the center as the tripod feet.

An additional means of keeping the foot rest directly above one of the tripod feet in the initial adjustment, and relieving the reduced end of the set screw of the stress which might shear it oli if a user ignorant ot' the construction in this respect should apply7 force-to the Ytoot rest to swing it around on the tripod stem, is seen at 20, 2U, Consisting ot' two lugs extending down from the yoke, 17"', constituting a 'fork which spans the tripod leg over which the toot rest is lodged. The lugs, 20, 20, are designed to be as long as the maximum desired vertical adjustment of the toot rest with respect to the tripod base; and they do not interfere with the entire removal ot' the foot rest when the use to which the stool is put renders its presence objectionable, for it will be understood that upon unscrewing the seat from the stem, or screwing the stem out from the base, the toot rest in its entirety can be withdrawn upwardly.

ln Figure 4l there is shown a simple form ot' removable back tor the stool consisting ot a unitary rod, al), bent in two V-shape'd loops, lll, 4l, and flexed horizontally at the necks of thesloops in an arc ot substantially 1800- 900 in each loop, the rodpbeing provided with shoulders formed by swaging as seen at 41a, near the ends, and threaded from the ends to said shoulders for engaging apertures, let", in the seat on whose upper side the shoulders, Lllt, are stopped, nuts, 51.2being applied below the seat on the threaded ends of the rod with washers, 42, it desired, above and below the web oi the seat. At the middle part, be-

low the loops, the rod may be bent as seen at below the seat web; and for convenience ot inserting and withdrawing` that ley, the flange of the seat may have an aperture registering on the position of the loop, 43, when the back is applied to the seat.

l do not limit mysella to this particular form of the removable bach which may be widely varied without departing from the invention, which, as to this part, consists in providing the stool seat with a back removable and replaceable at will.

l claim z- 1. A portable three-legged stool having a foot-rest ot such substantial angular extentthat being positioned with the middle portion ot said extent at the radial plane oi? one ot the legs its extremities are both contained between the radial planes bisecting the angles between said leg and the other two legs respectively.

2. A portable stool having a base with a central vertical stem and having a seat and a foot-rest both secured to and supported on said stein ot' the base, said seat and foot-rest being adjustable on the stem of the base axially ot said stem independently of each other, the means of securing the toot-rest adjustably on the stem of the base consisting of a longitudinally superiicial groove in the stem having vertically spaced-apart holes in the bottom ot' the groove, the toot-rest having a sleeve hub by which it is engaged with the base, and a set screw mounted in said toot-rest sleeve hub having its end dimensioned tor engaging' the holes. y

3. ln the construction defined in claim l, means tor assuring the position of the tootrest with'respect to the legs, as defined in said claim, consisting in the provision of a hub orp the toot-rest which constitutes a sleeve Jfor mounting it on theV stem of the base, said base stem having a longitudinal groove tor engagement by a set screw mounted in said sleeve-hub, the Vgroove having vertically spaced-apart holes corresponding to positions ot' vertical adjustment of the Jtoot-rest, the set screw having its end dimensioned tor engaging said holes when screwed in tor engaging the groove.

In testimony whereof, I have hereunto set my hand at Chicago, Iliinois, this 7th day oi June, 1926.

MICHAEL lV. MCABDLE.

Cil 

